The reason quickscoping is more popular on consoles is because of their "autoaim"/"autoadjust". On PC you actually need to have your enemy in the middle of the screen before you quickscope, while on consoles the brief aiming makes your aim go towards the person. Atleast it was like this in MW2.

well i'll admit i dont know the definition of quickscoping, but i play a lot of sniper in TF2. I wait until the last possible moment to scope in (is that quickscoping?) so that i can maintain maneuverability over my character.
Its worth mentioning that sniping mechanics are very different in TF2 than other games.

in that case, quickscoping is very useful in TF2. if you stay scoped in it makes you an easy target, as you cannot move. Most sniper V. sniper duels are won by waiting for the other guy to zoom in and miss, as there is a short lag between raising and lowering the weapon where you cannot move.